Shiva Purana
पंचाक्षरजपेनैव सर्वसिद्धिं लभेन्नरः । प्रणवेनादिसंयुक्तं सदा पंचाक्षरं जपेत् ३४ ।
The Japa of the five-syllabled mantra shall always be performed along with Praṇava. A man can achieve everything by means of the Japa of the five-syllabled mantra.
english translation
paMcAkSarajapenaiva sarvasiddhiM labhennaraH । praNavenAdisaMyuktaM sadA paMcAkSaraM japet 34 ।
hk transliteration by Sanscript